1. Field of the Invention
The present invention relates to a color filter device for a digital camera which makes it possible for a user to select a color, and method therefor. The present application is based upon Korean Application No. 26425/1996, which is incorporated herein by reference.
2. Description of the Related Art
Referring to FIG. 1, an optical signal incident upon a lens of a camera is converted to an electrical signal by a photoelectric converter 111 which may be composed of a charge-coupled device, for example. A signal detector 112 detects the size of a signal output from the photoelectric converter 111, and may be composed of a correlated double sampling, for example. A gamma corrector 113 receives a signal from the signal detector 112 and adjusts an input and an output to be proportional to each other by correcting a luminescence feature of the input signal. An analog-to-digital (A/D) converter 114 converts an output from the gamma corrector 113 into digital data. A luminance/color (Y/C) separator 115 separates the digital data of the composite video signal output from the A/D converter 114 into a luminance signal Y and color difference signals B-Y and R-Y, where Y, B-Y and R-Y are expressed as Y=0.59G+0.3R+0.11B, B-Y=-0.59G-0.3R+0.89B and R-Y=-0.59G+0.7R-0.11B, respectively.
The luminance signal Y and the color difference signals B-Y and R-Y may differ according to the treatment of the R, G, B signals and the characteristics of the photoelectric converter 111. A luminance processor 116 performs processing on the luminance signal Y from the Y/C separator 115. A color processor 117 generates a color signal C by processing the color difference signals B-Y and R-Y from the Y/C separator 115. The Y/C separator 115, the luminance processor 116 and the color processor 117 form a signal processor 100.
A digital-to-analog (D/A) converter 118 converts the luminance Y data from the luminance processor 116 to an analog signal and a D/A converter 119 converts the color C data from the color processor 117 to an analog signal. A luminance/color (Y/C) mixer 120 generates a composite video signal by mixing the luminance signal Y and the color signal C from the D/A converters 118 and 119, respectively. The composite video signal from the Y/C mixer 120 is applied to a view finder of a camera, the VCR of a camcorder, and a video signal output terminal.
Some camera systems comprise video input terminals for receiving the signal treated luminance data Y and color difference data B-Y and R-Y directly from the D/A converters. Accordingly, it is desirable for the camera system to be equipped with video output terminals for transmitting the treated Y, B-Y and R-Y signals in addition to the video output terminal transmitting the composite video signal. In the system as illustrated in FIG. 1, the video output terminals are installed to directly transfer the signals from the luminance processor 116 and the color processor 117.
The color data C composed of the B-Y and R-Y color difference signals is determined by a signal received from a lens of a camera. An optical signal received from the lens has its natural hue when a color filter is not used on the lens. When a color filter is used to change a color of a video signal in a camera, the changed color signal can not be changed a second time. So once the color of a video signal is changed using the color filter, it is impossible to change the color of the video signal during playback.